run-tests: add option for running with and without Rust extensions This provide a simple and clear way to run the test with or without rust.

run-tests: rename "pure" variable to setup_opts There are more useful flag than just `--pure`. We clarify the variable name before adding more options.

setup-rust: add a --no-rust flag This new flag will make sure the rust extension will not be build. If neither `--rust` nor `--no-rust` is specified the `HGWITHRUSTEXT` is used.

cext: drop the WITH_RUST block These were used by the `direct-ffi` mode that just got dropped.

setup: use printf instead of print Yuya Nishihara pointed `printf` to me, so I will respect the cargo cult.

git: don't fail import when pygit2 is not install `test-duplicateoptions.py` was failing on py2 for be because I didn't have pygit2 installed. It failed because we depend on pygit2 at import time. This patch makes it so we successfully load the git extension even if pygit2 doesn't exist -- we just won't be able to use it in that case. Differential Revision: https://phab.mercurial-scm.org/D8268

hghave: add a check for pygit2 This will make it easy to use availability of pygit2 as in conditions such as `#if pygit2` and `(pygit2 !)`. It also makes it a little clearer why the test case skipped (when that happens). Differential Revision: https://phab.mercurial-scm.org/D8267

localrepo: add git extension to autoextensions list Differential Revision: https://phab.mercurial-scm.org/D8266

gitlog: implement __iter__ on changelog This allows `hg phase --force --draft -r .` to work, for example. Differential Revision: https://phab.mercurial-scm.org/D8264

gitlog: fix embarassing bug that prevented log from showing correct parents We had the correct parents in the database, but the changelog was always returning p1 for all parents. Oops. Differential Revision: https://phab.mercurial-scm.org/D8263

git: add readfast() method to manifest Mysteriously, on a different system a handful of things don't work without this, including log. This is especially odd to be because log works in the test. In any event, it's legal for readfast() to just return read(), so that's what we do. Differential Revision: https://phab.mercurial-scm.org/D8262

git: make {shortest()} return shortest *unique* prefix It used to return the prefix of the specified length as long as the full node was unique (i.e. always). Differential Revision: https://phab.mercurial-scm.org/D8256

git: skeleton of a new extension to _directly_ operate on git repos This is based in part of work I did years ago in hgit, but it's mostly new code since I'm using pygit2 instead of dulwich and the hg storage interfaces have improved. Some cleanup of old hgit code by Pulkit, which I greatly appreciate. test-git-interop.t does not cover a whole lot of cases, but it passes. It includes status, diff, making a new commit, and `hg annotate` working on the git repository. This is _not_ (yet) production quality code: this is an experiment. Known technical debt lurking in this implementation: * Writing bookmarks just totally ignores transactions. * The way progress is threaded down into the gitstore is awful. * Ideally we'd find a way to incrementally reindex DAGs. I'm not sure how to do that efficiently, so we might need a "known only fast-forwards" mode on the DAG indexer for use on `hg commit` and friends. * We don't even _try_ to do anything reasonable for `hg pull` or `hg push`. * Mercurial need an interface for the changelog type. Tests currently require git 2.24 as far as I'm aware: `git status` has some changed output that I didn't try and handle in a compatible way. This patch has produced some interesting cleanups, most recently on the manifest type. I expect continuing down this road will produce other meritorious cleanups throughout our code. Differential Revision: https://phab.mercurial-scm.org/D6734

hg-core: add a compilation error if trying to compile outside of Linux For now, we can only provide support for Linux in `hg-core`, so we have to be explicit about it in case anyone wonders why their Dirstate is suddenly broken, or why the crate does not compile (on Windows for example). Differential Revision: https://phab.mercurial-scm.org/D8246

gzip: use the stdlib version with python 3 (issue6284) It turned out that the stdlib gained the feature we missed in python 3.1. We can now use it directly.

gzip: indent the custom Gzip code We need a new conditional in the next changesets (Adding 3.8 support). We do the large code move beforehand for clarity.

gzip: rename the argument to `mtime` to match upstream python Python gained the feature we missed in 3.1. The argument name is `mtime`. We align our version for consistency.

heptapod-ci: run the test from outside the test directory This will help detecting case where this is broken.

run-tests: fix conditional when tests are run outside of `tests` The logic to find `hghave` was using `__file__` but… non absolute path in `__file__` gets wrong as soon as we change directory (thanks python… you are being helpful). The rest of the `run-tests.py` code already deal with this fine. We simply reuse the `RUNTESTDIR` variable to fix it.

merge with stable

tests: use native string type for parsed hghave log lines Before this change, on Python 2, the parsed messages were decoded to unicode, causing an implicit conversion from unicode to str later.

tests: avoid implicit bytes -> unicode -> bytes roundtrip on Python 2 Before the change, there were two implicit conversions: * The format string was converted to unicode because the substituted values were unicode. * When printing the message in log(), the string was converted from unicode to str.

cext: make HgRevlogIndex_GetParents private again The rust's direct-ffi code need to access this function. Now that it `direct-ffi` is no more. We can make this function `static` again. This change was suggested by `Yuya Nishihara`.

setup-rust: remove the legacy 'direct-ffi' variant This variant have been abandoned for a while. Keeping it around just get people confused.

hghave: add a `rust` keyword to detect the use of compiled rust code The content of some on disk cache can varies when using rust (because it is faster to do so in the rust variant). So we need to be able to detect this case for some test. Differential Revision: https://phab.mercurial-scm.org/D8162

nodemap: check that a simple lookup works fine I realised the code was not exercised much. Differential Revision: https://phab.mercurial-scm.org/D8180

debuginstall: print if Rust extensions are installed This should make it easier to use the Rust extensions. Another patch on will be exposing a version and more useful information, but it can only be done on top of this very patch, since it is targeting the stable branch and the API has already changed on the default branch. Differential Revision: https://phab.mercurial-scm.org/D8248

nodemap: fix missing r-prefix on regular expression Looking at this regular expression, it's pretty obvious from reading it that it wanted to match literal ., but since the r was missing on the pattern it was matching any character. I guess we're just lucky nothing bad happened as a result. This was automatically fixed by pyupgrade, but I split it out into its own change because it seemed important. Differential Revision: https://phab.mercurial-scm.org/D8254

tests: use pyflakes module instead of pyflakes executable This results in that the pyflakes version specific to the configured Python version is used. This way, both the Python 2-specific and the Python 3-specific pyflakes are run by the test suite (depending on the configured Python version). For downstream projects which are using Mercurial’s test infrastructure and are not yet ported to Python 3 (e.g. hg-git) it ensures that the correct pyflakes version is run even when the system’s default pyflakes is the Python 3-specific one.

copies-tests: add a case where with merge with an overwritten files This is similar to the BF/FB case, but in this case, the other branch updated the file. So an actual merge happens and the two "independant" file history has to be merged. Differential Revision: https://phab.mercurial-scm.org/D8242

copies-tests: add a case where a file is deleted/added but with a merge This is a case similar to DB/BD, but in this case the other branch updated the file. So an actual merge happens and the two "independant" file history has to be merged. Differential Revision: https://phab.mercurial-scm.org/D8241

copies-tests: add a test with a rename overwriting another file This is a variation of the "BD" case, but this time, the file is not "new", it is overwritten by another file being renamed. Differential Revision: https://phab.mercurial-scm.org/D8240